[lwip-users] Connection timeout (sometimes)

[Roger Cover]

Greetings List,

A customer of mine has encountered a problem. The problem only occurs rarely. I 
have not seen it in my testing. The system is a few years old, so it was built 
using lwIP 1.2. I need some information to help with my debugging efforts. The 
symptoms are as follows:

Host computer sends a packet with the SYN flag set to open the connection.
lwIP sends a packet back with ACK set, but no SYN.
After a time, Host sends another SYN attempt.
lwIP sends another packet back with ACK set, but no SYN.

This can go on for over a minute. I have attached a WireShark packet capture 
demonstrating the issue. In the capture, the Host computer is at 192.168.1.1 
and the lwIP device is at 192.168.1.175.

As I mentioned, this device is using lwIP 1.2.
The software in the device uses the callback (raw) API.
The software is running without an OS.

Any information you can send me to guide my search for the cause would be 
helpful.

Regards,
Roger W. Cover
Spectral Instruments, Inc.
420 N. Bonita Ave.
Tucson, AZ 85745
Voice: 520-884-8821 ext. 144
FAX: 520-884-8803

20100821_161358.pkt
Description: 20100821_161358.pkt